1. Field of the Invention
This invention relates to devices for collecting and dispensing of liquids, particularly those liquids which are in a puddled form or in an open container. The device is particularly suited for the collection of blood from a blood drop.
Pipetting devices are known which employ capillary action to take a sample into the device. Such devices generally have a compressible (squeeze) bulb, usually with an opening in its wall. With the opening unobstructed, the sample fills a capillary tube. A finger is placed over the opening and the bulb is compressed to force the sample out of the tube. Manipulation of the squeeze bulb is, however, cumbersome. Such pipetting devices are not particularly useful in doctor's offices and diagnostic laboratories for taking small samples of, for example, blood from a puddle obtained by pricking a patient's finger.
Syringes for taking samples are also known. The syringe requires mechanical movements to fill the syringe with a sample and also to dispense the sample. Accurate sampling with a syringe usually requires a relatively expensive device. Ideally, the sampling portion of a sampling device should not be reusable. Consequently, the one-time use of a relatively expensive syringe is undesirable, but often unavoidable. In addition, the appearance of a syringe with a long needle often results in patient stress.
There is a need, therefore, for a sampling device which allows sampling without mechanical movement and dispensing of a precise amount of sample by means of mechanical movement.
2. Description of the Prior Art
A rinsing pipette is disclosed in U.S. Pat. No. 3,233,785. An apparatus for measuring precise microquantities of fluid samples is described in U.S. Pat. No. 4,003,262. A telescoping serum separator and dispenser is disclosed in U.S. Pat. No. 4,052,320. In U.S. Pat. No. 4,136,036 there is disclosed a collection and dispensing device for non-pressurized liquids. A device for the extraction of capillary blood is disclosed in U.S. Pat. No. 4,396,024.